What was the engine displacement of the first Jaguar E-Type?

The first Jaguar E-Type used a 3.8-litre engine.

Jaguar introduced the E-Type in 1961, initially with the company’s 3.8-litre version of the XK inline-six. The engine had triple SU carburettors and was related to the powerplant used in the XK150S and other Jaguar performance models. In the E-Type, it helped support the car’s famous combination of strong acceleration and a claimed 150 mph top speed.

The 3.8-litre engine belongs specifically to the earliest Series 1 cars, built from 1961 through 1964. In October 1964, Jaguar enlarged the engine to 4.2 litres. The later engine produced broadly similar peak horsepower but delivered substantially more torque and arrived with improvements such as an all-synchromesh gearbox, revised seats and upgraded electrical equipment.

That later 4.2-litre version is the most common source of confusion. It was important in E-Type history, but it was not the engine fitted to the first production cars. The 3.0-litre and 5.0-litre choices do not describe the original mainstream E-Type engine.